The invention relates to the field of methods and devices for the treatment of obstructive sleep apnea, and more particularly to opening the airway of subjects with symptoms of obstructive sleep apnea.
Sleep apnea is defined as the cessation of breathing for ten seconds or longer during sleep. During normal sleep, the throat muscles relax and the airway narrows. During the sleep of a subject with obstructive sleep apnea (OSA), the upper airway narrows significantly more than normal, and during an apneic event, undergoes a complete collapse that stops airflow. In response to a lack of airflow, the subject is awakened at least to a degree sufficient to reinitiate breathing. Apneic events and the associated arousals can occur up to hundreds of times per night, and become highly disruptive of sleep. Obstructive sleep apnea is commonly but not exclusively associated with a heavy body type, a consequence of which is a narrowed oropharyngeal airway.
Cyclic oxygen desaturation and fragmented sleeping patterns lead to daytime sleepiness, the hallmark symptom of the disorder. Further consequences of sleep apnea may include chronic headaches and depression, as well as diminished facilities such as vigilance, concentration, memory, executive function, and physical dexterity. Ultimately, sleep apnea is highly correlated with increased mortality and life threatening comorbidities. Cardiology complications include hypertension, congestive heart failure, coronary artery disease, cardiac arrhythmias, and atrial fibrillation. OSA is a highly prevalent disease conditions in the United States. An estimated 18 million Americans suffer from OSA to degrees that range from mild to severe, many of whom are undiagnosed, at least in part because the afflicted subjects are often unaware of their own condition.
Treatment of OSA usually begins with suggested lifestyle changes, including weight loss and attention to sleeping habits (such as sleep position and pillow position), or the use of oral appliances that can be worn at night and help position the tongue away from the back of the airway. More aggressive physical interventions include the use of breathing assist systems (such as continuous positive airway pressure machines) that provide a positive pressure to the airway through a mask worn by the subject. In some cases, pharmaceutical interventions can be helpful, but they generally are directed toward countering daytime sleepiness and do not address the root cause. Some surgical interventions are available, such as nasal surgeries, tonsillectomy and/or adenoidectomy, reductions in the soft palate or the uvula or the tongue base, or advancing the tongue base by an attachment to the mandible and pulling the base forward. These surgical approaches can be quite invasive and thus have a last-resort aspect to them and simply do not reliably alleviate or cure the condition. There is a need for less invasive procedures that show promise for greater therapeutic reliability.
Related devices and methods are described in U.S. patent application Ser. No. 11/969,201, filed 3 Jan. 2008, the disclosure of which is incorporated herein by reference.